The duration of anticoagulation bridging therapy in clinical practice may significantly exceed that observed in clinical trials

Abstract

The duration of LMWH bridging therapy in practice may be significantly greater than previously reported in clinical trials, and the incidence of patients requiring prolonged (>14 days) LMWH therapy is relatively high. Outpatient LMWH as employed in clinical practice safely bridges patients to oral anticoagulation. Strategies to shorten the duration of LMWH therapy are needed and are likely to improve clinical outcomes and reduce health care expenses. In prospective clinical trials low-molecular-weight-heparin (LMWH) has proven effective in transitioning patients with venous thromboembolic disease to therapeutic warfarin anticoagulation. However, it is unknown if the anticoagulation results obtained in these trials, which involved rigidly performed anticoagulation monitoring, are achieved in standard clinical practice involving patients with a variety of indications for anticoagulation. We conducted a retrospective analysis of 100 patients initiating warfarin while receiving LMWH under the management of a university-based anticoagulation management service. The mean total duration of LMWH therapy was 12.0 +/- 8.2 days, of which 9.8 +/- 8.0 days (median 7.5 days; interquartile range 4.3-13.0 days) occurred in the outpatient setting. Forty-one percent of patients received outpatient LMWH for <7 days, 40% for 7-14 days, and 19% for >14 days. We conclude that the duration of LMWH bridging therapy in practice may be significantly greater than previously reported in clinical trials, and the incidence of patients requiring prolonged (>14 days) LMWH therapy is relatively high.

Dosing Options for Decreasing the Time to Achieve Therapeutic Anticoagulation When Reinitiating Warfarin: A Case Series

“…Data from an AMS assessing the duration of LMWH necessary in those new to warfarin therapy showed that a median duration of 7.5 days (IQR 4.3-13.0 days) was required. 12 This prolonged duration of LMWH use is consistent with our experience, yet inconsistent with that reported in randomized controlled trials assessing LMWH in the setting of venous thromboembolism, which showed a mean duration of 6 days of LMWH. [13][14][15] Historically, many clinicians have been Table 5).…”

Warfarin Dosing and Time Required to Reach Therapeutic International Normalized Ratio in Patients with Hypercoagulable Conditions

“…Kovacs et al found that patients who were initiated with 10 mg of warfarin achieved therapeutic INR 1.4 days earlier than those who received 5 mg [13]. One study concluded that initiation with 5 mg of warfarin was associated with 5.6 days of bridging with low-molecular-weight heparin [14]. The American College of Chest Physicians recommends initiation with 10 mg in patients healthy enough to be treated as outpatients, with dose modifications done as per the INR after 2 days [7].…”

Case studies in anticoagulation management

“…After warfarin is initiated, the peak INR may be delayed by 3-5 days, increasing the patient's risk of a thromboembolic event [5]. Bridging therapy includes a minimum of 5 days of LMWH (with warfarin initiated on day 1 of LMWH) and continued until two consecutive, therapeutic INR results have been obtained [9][10][11][12][13][14][15][16].…”